Surgical tools are commonly known in the art as valuable aids for surgeons performing surgical procedures. Such surgical tools may be especially helpful in minimally invasive surgery (MIS), or surgical procedures that are performed through incisions that are considerably smaller than incisions used in traditional surgical approaches. In an orthopedic application such as total knee replacement surgery, for example, an MIS incision length may be in a range of about 4 to 6 inches whereas an incision length in traditional total knee surgery is typically in a range of about 6 to 12 inches. Although MIS procedures are more difficult to perform due to the limitations associated with smaller incisions, there are several advantages to the less invasive MIS procedures which promote continued use thereof. For instance, the smaller incisions of MIS procedures may help minimize trauma to soft tissue, reduce post-operative pain, promote earlier mobilization, shorten hospital stays and speed rehabilitation of the patient. Accordingly, it is a shared goal in the art to overcome the common drawbacks associated with MIS procedures and minimize the difficulties surgeons face while performing MIS procedures.
One drawback of MIS is that the small incision size reduces a surgeon's ability to view and access the anatomy of a region of interest or surgical volume. For example, in minimally invasive orthopedic joint replacement, limited visibility and limited access to the joint increase the complexity of assessing proper implant position and of reshaping bone. As a result, accurate placement of implants may be more difficult. Conventional techniques for counteracting these problems include, for example, surgical navigation, positioning the leg for optimal joint exposure, and employing specially designed, downsized instrumentation and complex surgical techniques. Such techniques, however, typically require a large amount of specialized instrumentation, a lengthy training process, and a high degree of skill. Moreover, the operative results among various surgeons may not be sufficiently predictable, repeatable and/or accurate. In other related applications, due to the limited visibility of MIS procedures, the surgeon may refer to a display screen through which the surgeon may view a two- or three-dimensional model of the region of interest derived from compilations of medical images.
A common drawback of both MIS and traditional surgical approaches in orthopedic applications is that healthy as well as diseased bone is removed during preparations for an implant. For example, a total knee replacement can require removal of up to ½ inch of bone on each of three compartments of the knee. One conventional solution for preserving healthy bone is to perform a partial, unicompartmental or multicompartmental, knee replacement, which involves removal of damaged or arthritic portions on only one compartment of the knee. Such an approach may rely on freehand sculpting of bone with a spherical burr through a minimally invasive incision typically about 3 inches in length. While the spherical burr enables cuts having rounded shapes which cannot be reproduced with a surgical saw, the freehand burring technique is difficult to master and requires more artistic sculpting capability from the surgeon than techniques employing traditional cutting jigs or saw guides. Accordingly, while freehand cutting requires a high degree of skill to achieve operable results that are sufficiently predictable, repeatable and/or accurate, unicompartmental and traditional surgery typically result in the removal of at least some healthy bone along with the diseased and/or damaged bone.
One approach to orthopedic surgeries makes use of autonomous robotic systems to aid the surgeon. A drawback of the use of autonomous robotic systems is that such approaches do not enhance the surgeon's inherent surgical skill in a cooperative manner. Such systems, however, primarily serve to enhance bone machining by performing autonomous cutting with a high speed burr or by moving a drill guide into place and holding the position of the drill guide while the surgeon inserts cutting tools through the guide. These systems act autonomously rather than cooperatively with the surgeon, and thus, require the surgeon to cede a degree of control to the robot. Additional drawbacks of autonomous systems may include poor ergonomics, the need to rigidly clamp the bone during registration and cutting, increased incision length for adequate robot access, and limited acceptance by surgeons and regulatory agencies due to the autonomous nature of the system.
Accordingly, there is a need for a more simplified surgical device, system or method that provides for more predictable, repeatable and accurate surgical procedures. More specifically, there is a need to minimize the amount of healthy bone that is removed with damaged and/or diseased bone, minimize autonomous control and increase the overall control of the surgeon performing surgical procedures. Furthermore, there is a need to enable the surgeon to maintain direct visual contact with the anatomy and to reduce any latency associated with surgical or guide tools.